So I basically got a 03 G35 6MT with a defect. 68k miles for $7800 It usually takes two starts to turn on engine. Just giving background info. I got the code for one of the camshaft sensors going bad. I have replaced both camshaft sensors and the crankshaft recently. Still have the same problem. My mechanic replaced the last sensor (angled sensor) and said the car stopped throwing codes. So I guess it's not the sensors. Then said it might be the fuel pump and is currently working on my car right now.

Here are some of the symptoms:
-Cranks twice then starts
-sometimes takes up to 8+ (lost count after so many) cranks to start
-will randomly hiccup or jerk with driving at low or high rpms.
-if I turn off the car and immediately turn it back on it idles very slowly but will turn on, on first crank
-not a symptom really but fuel gauge is not working


I want to share my experience with everyone in order to make this forum more awesome. Hopefully we find out what it is and I can share it with you.

 

2005 G35x sedan 103K miles.

I'm having similar issues, very long starts. I was told by a mechanic that it may be my fuel pump, I have not replaced my camshaft sensors yet. He advised me to drive my car for 20-30 mins park it for 20 mins and try to start the car. Every time I did that the car took a long time to start. Then after that long start I immediately turn the car on and off 5 times with no issues.

Not sure if I should start with replacing the camshaft sensors or just replace the fuel pump.

With the troubleshooting tips that my mechanic had given me sounds like the fuel bump may be bad but replacing the camshaft sensors has fixed many issues other G35 drivers have that are similar.

Let me know how you make out.

 

Well after more digging around we tested the pump and it's all good. I guess it's back to the sensors then. Ill admit I bought cheap autozone ones. I'll keep you updated. Well if it were your camshaft or crankshaft you should have the SES light on your dash? If not then it might be your pump. You should test it!

 

faulty sensors wont always throw a code but will give you problems. I tried aftermarket sensors my car didn't agree. so I stick to oem sensors from now on

 

Then how would you know what sensor to replace? I'm betting all my money on the bottom crank sensor on my car. What aftermarket sensors did you put?

 

there will be cases where the sensor will work just not at 100% . it wont throw a code but jus isn't running right. ive tried the cam sensor from orielys. when I tried the orielys sensor everytime I did the idle reset at the last step where u start the car my car would die. car also wasn't idling right. so something wasn't right but had no codes after the repair. so I returned it and went oem. theyre about the same price online but I needed the sensor asap so that's why I went with orielys plus they had lifetime warranty I think . the cars not gonna throw a code for every single thing that goes wrong on the car.

 

I brought my car to the dealer to diagnosis my starting issue they indicated the my fuel pump was failing and quoted me $1400 to replace it. So I bought the fuel pump for $270 and will be installing it hopefully next weekend. I'm hoping that will resolve my starting issues.

 

Update on my starting issue. Replaced the fuel pump and I am no longer having any starting issues. Took min 10 mins to replace. The fuel pump was easy to get to. It was location under the rear seat.